Chevron inspection missed suspected pipe at Richmond refinery

Chevron says a corroded pipe segment that may have caused the recent fire was not included in a prior inspection and could have been unusually susceptible to corrosion.

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By BEN LEFEBVRE

Chevron said Tuesday a corroded pipe segment that is the
focus of an investigation into the August fire at the company's
refinery in Richmond, Calif., had not been included in a prior
inspection and may have been unusually susceptible to
corrosion.

Chevron and government officials are still investigating the
cause of the fire at the 245,000 bpd refinery that sent black smoke
billowing over the San Francisco Bay and area residents to
hospital emergency rooms.

The Chemical Safety and Hazard Investigation Board had said
earlier that the walls of a pipe leading from the refinery's crude distillation unit had corroded by
80%, making it at some segments as thin as a penny and likely
to leak flammable material.

Chevron said Tuesday the pipe had an unusually-low silicon
content, making it vulnerable to corrosion in high temperatures
because of a process called sulfadation.

The company didn't check a 5-foot segment of the pipe during
a routine inspection in November despite having removed a
nearby pipe that showed signs of corrosion.

Unfortunately, we did not inspect the individual
component that failed, said Nigel Hearne, general manager
of the refinery. We are now inspecting every individual
component in carbon steel systems exposed to
sulfadation corrosion conditions.

Chevron said Monday that the UW Environmental Protection Agency was
conducting a separate, criminal investigation into whether the
Richmond refinery was illegally routing gas away from emissions monitoring equipment
before flaring it into the air.

The Richmond refinery is the largest in the San
Francisco Bay Area and accounts for nearly 10% of the refining capacity in the US West
Coast. It produces gasoline, diesel fuel and assorted petrochemicals. The production
outage following the August fire caused California gasoline
prices to rise 30 cents.

The API 571 explains all kind of corrosion encountered on refineries piping process plants.Also the API give us a good idea on how to prevent corrosion mechanisms on certain piping circuits of selected process.Hydrogen Sulfide corrosion is treated extensively as well as distillation tower corrosion. This problem is well recognized and treated in this API.

Larry10.03.2012

When I was an engineering student, I worked as an inspector checking piping thickness. Inspection is not 100% coverage and is based on representative samples. I can imagine it would be very easy to miss a 5' section of pipe, particularly if the line was insulated.

Mujahid10.03.2012

Pipeline inspection is very important part of operation specially for subject products.chemicals, It is also un acceptable that"The company didn't check a 5-foot segment of the pipe during a routine inspection in November despite having removed a nearby pipe that showed signs of corrosion"

Youyu Lu10.02.2012

It's so sad that "an accident" happened to such a big company! Lots of lessons learnt from this incidnet. In term of "Si" content, I still often heared that all crbon steel pipe are "killed" but actually, it's not.

Alberto Jimenez09.29.2012

As always, this will be called " an accident ", but ; why the "company didn't check a 5-foot segment of the pipe during a routine inspection in November" ?. Seems to be impossible in the San Francisco largest Refinery. Who is the responsable, the Director, the President of the Company, or anybody, as always ?.

Jayaprakash Edapparampil09.28.2012

The most difficult part of inspection in any industry is to include all bits and pieces of piping in inspection program. My experience is that every company will have a comparetively better and strong inspection program for Equipment (pressure vessels, tanks etc.) but usually a weak program for piping. This is due to the complicated network of piping. 100% management support, resources and dedicated inspectors are essential for a succesful inspection program for piping